Codominance

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codominance

[kō′däm·ə·nəns]
(genetics)
A condition in which each allele of a heterozygous pair expresses itself fully, as in human blood group AB individuals.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Codominance

 

expression in heterozygotes of characters typical of both forms (alleles) of the gene.

Codominance is found, for example, in studying blood serum proteins (transferrins). In individuals heterozygous for the alleles controlling the biosynthesis of transferrin, both forms of this protein are present in the blood at the same time, and each form is found separately in the corresponding homozygote. The same patterns of heredity are also found in other proteins, including almost all the enzymes. The degree of activity of each of the allelic genes may be different. The products synthesized under the control of two alleles of the same gene may independently influence the expression of a character or they may interact with each other. The existence of codominance is useful in studying the genetic structure of populations without making crossings or studying pedigrees; instead, modern biochemical and immunological methods of separating proteins are used. Codominance in erythrocytic antigens facilitates the identification of blood groups in man and animals.

V. S. KIRPICHNIKOV

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
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To classify settlements take the following steps: 1) determine weights of indices; 2) assign qualifications to all qualitative indices; 3) determine utilities of quantitative indices using equations (1), (2), (3), associating scoring scales to the qualifications of qualitative indices, and fill in the matrix of utilities; 4) compute coefficients of concordance using equation (4) and fill in the matrix of coefficients of concordance A; 5) compute coefficients of discordance using equation (5) and fill in the matrix of coefficients of discordance B; 6) determine dominance relationships and represent them graphically; if there are too many settlements, the construction of the graph becomes difficult; and 7) rank settlements based on the determined dominance relationships.
To determine dominance relationships use the following algorithm: start from the concordance threshold p = 1 and discordance threshold q = 0 and look for settlements [L.sub.g] and [L.sub.k] such that [C.sub.gh] = 1 and [D.sub.gh] = 0.
It turns out that the measure of risk aversion plays a very critical role in characterizing a change in risk that may be represented by higher order stochastic dominance relationships. In this section assuming a lognormal distribution of the random return, R, we explore the role played by the risk aversion parameter, [epsilon], when the distribution function undergoes a shift that is more general than the FSD or the SSD shift.
In addition, the rank reversals that were observed could have resulted from the single losing experience of the dominant (after the previous win), "resetting" the dominant to subordinate status, and thus having two new subordinates re-forming a dominance relationship with equal opportunity for each animal to obtain higher rank.
At the beginning of the first phase (P1; 0-20 min), the divider was removed and the animals were allowed to interact and to establish a dominance relationship. At the beginning of the second phase (P2; 20-40 min), or the intruder phase--and depending on the experimental condition (see next section)--a third animal (intruder) was added to the original pair or to each member of the pair.
Because of the relatively high levels of aggressiveness reported for heteromyid rodents, we expected that dominance relationships within pairs would be obvious.
Dominance relationships of the dark kangaroo mouse (Microdipodops megacephalus) and the little pocket mouse (Perognathus longimembris) in captivity.
Thus, with the formation of dominance relationships, fighting tapers off, and the duration and intensity of encounters can be used as measures of "willingness" to fight (1).
These dominance relationships tended to be strong and quick to form, evident by the fact that dominance was formed by day 1 (data not shown) and that nearly half of the TLN animals (4/9,44%) were killed by their WT counterparts during the first week of pairing.
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We did not investigate age effects in our studies; however, to complete the understanding of the function of color in dominance relationships in the house finch, further studies need to be conducted that focus on responses of immature and adult brown-plumaged birds and their responses to plumage manipulations.